2006 Yamaha F115 - Boggs

[Jgatnarek]

Hey guys,

I have my Yamaha 115, with roughly 700 hours on it.
it starts right up and seems fine however once I put it under load 3-4000rmp it will bog down.... and won’t get up on plane.
now it’s done this a few time over the past 2 months or so..
to get it to work I reduce throttle , then hit it again I’ve noticed the problem getting worse and worse example this past week it took 3-4 try’s of throttling (idle to 45xRPMs)to get it up on plane and cruising ..however once on plane the 1st time it’s perfectly fine the rest of the day .. as like if nothing ever happened.

im new to all this and however I do have some dirt bike and motorcycle experience , everything with a boat is semi-new
i have recently done a 100
hour service by myself so I was think I maybe messed something up ...

the spark plugs haven’t been changed in about 150 hours , could this be a problem ? Bad gas ? Air in fuel line ?
fuel filter problem ,?

any thought would be much appreciated

thanks - Joel

 

[rejesterd]

Hello.

I would suspect a fuel issue more than a spark issue, but replacing plugs doesn't make a huge dent in your wallet and it could possibly be the problem.

But it sounds more like something is gummed up in the fuel system or the mechanical fuel pump isn't working properly. The pump is easy enough to take apart, but a quicker (and maybe a less invasive) test would be to disconnect the vacuum sensing hose from the pressure regulator. Then see if it runs better. If it does, I would say your fuel pressure is too low (which would point more to a clog in the injectors and/or the vapor separator, and not toward the mechanical fuel pump).

With the vacuum sensing hose disconnected, the pressure regulator will allow for a slightly higher fuel pressure than it normally would when connected to the air intake. This added pressure is needed to increase the fuel supply when you open the throttle quickly during acceleration. So when you run with the sensing line disconnected, it might not accelerate as quickly, but that extra bit of fuel pressure could be enough to get you over the edge of bogging. If things are really gummed up, this test won't tell you much. You will also run slightly rich during the test, but you shouldn't notice any negative effects.

At the end of the day, you might have to go through the fuel system entirely.. you can send the injectors in to be ultrasonically cleaned and repaired, change the fuel filter, change the filter inside the vapor separator, and try cleaning out the pressure regulator with some SeaFoam spray (or something similar).

 

[QBhoy]

I’d be right in about that fuel filter change and same with plugs. Dead easy and quick to rule them out.

 

[Captain Mustard]

I don't know your motor, but I had a 90hp 2stroke with similar symptoms. Tried just about everything, then discovered a loose magnet under the flywheel. Just saying...

 

[Jgatnarek]

first of all, I want to thank everyone for their reply ...


Fuel filter was just changed .. but maybe I can open it up, see if there is any damage. ? Also sure the spark plugs is a cheap little fix and could use a change anyways . I had the injectors cleaned last year ultrasonic and it helped a lot, so maybe this could be that again. Thanks for the responses